1. Field of the Invention
The present invention relates to a digital-analog converter for converting a digital signal to an analog signal.
2. Description of the Related Art
As digital signal processing techniques advance, signal processing techniques for converting an analog signal into a digital signal and converting the digital signal back into the analog signal are widely used and amounts of data processing used by various wired and wireless communication systems using the signal processing is increasing. Hence, an amount of digital signals to be converted to analog signals is increasing, and a digital-analog converter having a high conversion speed and high resolution is needed.
Digital-analog converters which sample an input signal at a Nyquist rate are provided by related art. Such digital-analog converters may achieve high resolution in theory as a number of bits increases, but it is difficult to attain a high resolution over 6 bits because of distortion arising from fabrication error. Digital-analog converters which produce the analog signal by combining current cells according to the input bits are also provided by the related art. The combination of the current cells allows for relatively low fabrication error and thus realizes a digital-analog converter of high resolution bits. However, an N-bit digital-analog converter requires 2N−1-ary current cells. Accordingly, the more bits, the more current cells needed. Furthermore, as the number of the current cells increases, a total area of the digital-analog converter expands and thus an Integrated Non-Linearity (INL) error may increase.
Accordingly, a related art method may reduce the INL error by randomly changing a pointer according to an input signal level every hour and using a different current cell every hour. However, the related art method may not reduce a Differential Non-Linearity (DNL) error indicating an error between the current cells, and thus reliability of the output signal per hour may be degraded. Furthermore, when a high-resolution digital-analog converter over 10 bits is realized using the related art method, more than 1,023 cells are necessary. As a result, implementing a circuit for randomly using more than 1,023 cells may need a complicated manufacturing process and a manufacturing cost rises due to the increase of the total area of the digital-analog converter.
Therefore, a need exists for a system and method for a digital-analog converter having a high conversion speed and high resolution.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present invention.